1999 

 NATIONAL OVERVIEW 



Adequacy of Scientific 

 Information and Assessments 



One of the most important national issues is the quaHty and quantity ot data on 

 which stock assessments and management decisions are based. Stock assessments and other 

 scientific information are the foundation for the rational and sustainable utilization of 

 renewable resources. Stock assessments require data on the biology ot the species, catches, 

 abundance trends, and stock characteristics such as age composition, which are put to- 

 gether to estimate the current status of the stock and its past history. This understanding 

 aids managers in the selection oi fishing targets to be achieved and thresholds or limits to 

 be avoided. 



Basic information is still lacking to construct adequate assessments for many U.S. 

 LMR's. This is the main reason why 21% of the stocks reported in Units 1-20 have un- 

 known utilization levels (Tables 3 and 4). These stocks of unknown status account for less 

 than 3% of the U.S. RAY, but include important species, such as sharks and many reef fish, 

 for which not even the catch is recorded on a species-by-species basis. Progress has been 

 made during the last few years, as 14 stock groups whose utilization level was unknown in 

 OLO '92 are now of known status (Table 11). But sound, scientifically based fisheries 

 management requires more than the ability to classify the status of stocks. Relatively pre- 

 cise estimates of actual abundance, fishing mortality, and potential yield (e.g. CPY and 

 LTPY) are more desirable. To improve on these estimates, more comprehensive data and 

 research are needed. 



Weighing a subsample of 

 longspine thornyhead rock- 

 fish, west coast upper con- 

 tinental slope assessment 

 survey- 



The recent study of stock assessment methods conducted by the National Academy 

 of Sciences (NRC, 1998) suggests that one of the key pieces of information required to 

 assess a stock is an adequate index of relative abundance. Abundance indices can be ob- 

 tained from analyses of catch rates in the fishery, or from scientifically designed research 

 surveys. The former type is often problematic because fishing operations tend to occur in 

 areas of high fish densirv', thus introducing potential biases of serious consequence. For 

 instance, an increasing trend in the efficiency of fishing operations over time could mask a 

 decline in abundance. Research surveys do not suffer from the same problem, but they 

 tend to be more imprecise and survey data are more expensive to collect. 



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